Method of manufacturing container closures



June 7, 1938. J, J, \MLUAMS 2,119,630

METHOD OF MANUFACTURING CONTA INER CLOSURES Filed Aug. 51, 1936 HIE? m 9Z, 41 1H4; V

J0 22 J0 27 i 15 z V w Wag/m Patented June 7, 1938 UNITED STATES PATENTOFFICE METHOD OF MANUFACTURING CONTAINER CLOSURES Application August 31,1936, Serial No. 98,774

4 Claims.

The invention relates to an improved method of manufacturing metal screwcaps of the continuous or the interrupted thread type, and particularlyto that type of thread cap in which the 3 bead or wire edge at the.lower edge of the cap skirt, is incurled instead of being outcurled.

While thread caps having an incurled wire edge or bead are old, yetheretofore they have been diflicult to manufacture. One of the objects.0 of the present invention is to provide a method by which the rate ofproduction of. thread caps having an incurled bead, can be greatlyincreased.

Another object of the invention is to provide l a method ofmanufacturing caps of this type, by

which the caps will be formed with great accuracy, thereby veryconsiderably reducing the loss of caps due to rejection aftercompletion.

Various other objects and advantages of the invention will be apparentto those skilled in the art, from the following detailed description,when taken in connection with the accompanying drawing; in which Figure1 is a vertical sectional view of the appa- 5 ratus for incurling thebead; the die being shown in elevated position.

Figure 2 is a fragmentary vertical sectional view of the same apparatus,but showing the die in lowered position.

Figure 3 is a vertical sectional view of the apparatus for reshaping theblank after the formation of the bead, but prior to the threadingoperation; the die being shown in elevated position.

Figure 4 is a fragmentary vertical sectional view of the same apparatus,but showing ,the

die in lowered position,

Figure 5 is a vertical sectional View of the original blank. Figure 6 isa vertical sectional view of the blank after the incurled head has beenformed. Figure 7 is a vertical sectional view of the blank after it hasbeen reshaped, prior to rolling the threads; and Figure 8 is a verticalsectional View of the completed cap.

Referring to the drawing in more detail, numeral I indicates a blankhaving a top 2 and a skirt 3. This blank is placed upon a plug 4 by anydesired means. A resiliently mounted centering plate (not shown) may beassociated with the plug. This plug 4 is mounted on a die block 5, whichis secured to the bolster plate of an ordinary punch press (not shown),or to any other desired machine.

Numeral 6' indicates a die holder, which is secured to the ram of anordinary punch press (not shown), or to any'other desired mechanismproviding a reciprocating movement. Numeral 1 refers to a guide orcentering ring which 5 is attached to the die holder, and which has asnug fit with the cap blank I; the lower end of the centering ring beingpreferably flared, as indicated by numeral 8.

The curling ring or die is referred to by nu- 10 meral 9. It is mountedin the die holder, and is provided with a continuous annular gro'oveII], which in the form illustrated is substantially semi-circular incross section. Numeral ll refers to a clamping and ejector pad, havingan up- 15 wardly extending stem l2. Arranged about the upper end of thestem is a coil spring l3; the lower end of the spring being seated inthe upper end of the die holder 6, and the upper end of the springbearing against a washer l4. Within 6 the holder there is arranged aboutthe stem l2 a heavy coil spring l5; the upper end of the spring bearingagainst the holder, and the lower end thereof bearing against a washerl6.

As the ram of the press descends, the guide or centering ring I snuglyfits around the cylindrical cap blank I, to center the blank withrespect to the descending die or' curling ring 9. This guide orcentering ring also supports the skirt of the blank to prevent anyoutward bulging of the skirt when the die acts on the edge of the blank.The clamping pad now engages the base of the blank and firmly holds itin position. The pad now remains stationary but the curling ring or diecontinues to descend against the pres 35 sure of spring IS. Thecontinued descent of the die holder brings the annular groove [0 of thedie 9 into contact with the upstanding edge of the blank, and as the diedescends farther the metal of the skirt is curled inwardly to form the40 incurled bead ll on the blank, as shown in Figures 2 and 6.

The die holder now moves upwardly, and during the first part of theupward movement the pad is held stationary'against the cap, by reason of45 the spring i5. The cap is thus removed from the die, but it remainsin the centering ring I because of the snug fit. As the upward movementof the holder continues the die ring 9 and washer l6 come together,whereupon the pad 50 rises with the holder. During the continued upwardmovement the stem [2 of the pad strikes a stop (not shown) on the press.This causes the upward movement of the pad to be stopped while theholder and its associated parts, including 55 the centering ring,continue to rise, the spring l3 being compressed. The blank with theincurled bead is thus ejected from the centering ring. While I havedescribed in detail the specific apparatus disclosed here, it is to beunderstood that the invention is not limited to any specific apparatus,or to any apparatus for ejecting the blank after the curling of thebead. So far as the step of incurling the bead is concerned, the onlyapparatus required is the plug to receive the blank, a die having acontinuous annular groove, and means for reciprocating the die.

The original blank has now been provided with a continuous'incurled beadH, the cap in its present incomplete form being referred to by numeralH3. The reshaping of the cap or blank l8, preparatory to the threadingoperation, will now be described; reference being had particularly toFigures 3, 4 and 7.

Numeral I9 refers. to the plug of a second die which, as in the case ofthe first-described die, may be secured to the bolster plate ofan'ordinary punch press or to any other desired machine. The upperportion of the plug, referred to by numeral 20, is of a diameter equalto the desired diameter of the finished cap, and the depth of thisportion is equalto the depth of the blank i8. At the point where theupper reduced portion 20 of the plug merges with the lower portion, anabrupt shoulder 2| is formed.

The blank I8 is inverted and placedon the plug l9 by any desired means.When 's'o positioned the incurled bead I'i rests on the shoulder 2|, thetop of the blank rests on the top of the plug, and the skirt of theblank is spaced from the reduced portion 20 of the plug, as indicated bynumeral 22. The blank mounted on the plug, ready for the reshaping orreducing operation, is shown in Figure 3.

Numeral 23 refers generally to a die which, as in the case of thefirst-described die, may be secured to the ram of an ordinary punchpress, or to any other desired mechanism providing a reciprocatingmovement. The interior 24 of this die is of ,a diameter only veryslightly greater than that of the reduced portion 20 of the plug.Numeral 25 refers to a shoulder which is followed by an enlarged portion26 of substantially the same diameter as that of the exterior diameterof the bead l1, and below the enlarged portion 26 there may be provideda flared portion 21.

As the 'die descends the shoulder 25 of the die engages the blank, andthis shoulder together with the portion 24 of the die and the portion"20 of the plug draw and reshape the blank to conform to the diameter ofthe reduced portion 20 of the plug. The blank as reshaped is referred toby numeral 28, and is shown in Figs. 4 and '7.

It will thus be noted that the blank has been considerably reduced indiameter above the incurled bead l'l; the bead remaining insubstantially its original shape and position, as the downward movementof the die stops before the shoulder 25 of the die engages the bead.While the bead remains in substantially its original position, yet withrespect to the skirt of the cap it has been relatively moved outward.That is, the reduction of the diameter of the skirt is the equivalent,relatively, to moving the bead outwardly. The blank is now in conditionto be placed on an ordinary threader to form any desired containerengaging means, such as the threads 29. The cap is thus completed, andis shown in Figure 8, where the finished cap is referred to by numeral29'.

' The reduction in the diameter of the cap skirt from that shown inFigure 6 to that shown in Figure 7, makes it possible to thread theskirt, for it will be understood that if the skirt as shown in Figure 6were threaded, the cap would not be practical for the incurled beadwould interfere with the threads so the cap-couldnot be screwed on acontainer. And it will be understood that this process assures afinished cap of the exact size desired, for. the blank is drawn orshaped over the reduced portion 20 ofv the plug to the exact size of theplug.

If desired, the die 23 may be provided with an ejector pad 30. In thespecific form illustrated the pad is carried by a stem 3| which isnormally held in elevated position with respect to the die by a coilspring 32. The pad in its normally elevated position with respect to thedie. is shown in Fig. 4, and in this particular construction the paddoes not contact with the metal blank even whenthe downward movement ofthe die has been completed. When the die is lifted the ejector padremains in elevated position relative to the'die, until the continuedupward movement brings the stem 3| into engagement with a stop (notshown). The pad then remains stationary while the upward movement of thedie continues, thereby ejecting the blank. The die ciently andinexpensively manufactured at a very high rate, and that the capsmanufactured by this method will be of the exact size desired.

Having fully described the invention, what I claim is:

1. The method of manufacturing metal closures from a blank having acylindrical skirt, which comprises curling inwardlythe free edge of theskirt to form an incurled bead inwardly v of the skirt, changing therelative position of the bead and skirt so that the bead projectsoutwardly of the skirt, and forming container engaging means in theskirt.

2. The method of manufacturing metal closures from a blank having acylindrical skirt, which comprises curling inwardly the free edge of theskirt to form an incurled bead, by a die shaping operation decreasingthe diameter of the skirt only, and forming container engaging means inthe skirt.

3. The method of manufacturing metal closures from a blank having askirt, which comprises forming with a die an incurled head inwardly' ofthe skirt, and with a second diereducing the diameter of the skirtwithout changing the diameter of the bead, so that the bead projectsoutwardly of the skirt.

4. The method of manufacturing metal closures from a blank having askirt, which comprises forming with a die an incurled bead inwardly ofthe skirt, with a second die changing the relative position of the skirtand bead so that the bead projects outwardly of the JOHN J. WILLIAMS.

